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charset="utf-8" This rejects bogus xenstore node values that include interior NUL bytes. These would be truncated by functions that expect NUL-terminated strings. Signed-off-by: Demi Marie Obenour --- drivers/xen/xenbus/xenbus_xs.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c index 12e02eb01f5991b31db451cc57037205359b347f..7cb2a22a7698ac40c81add23476= 594d9f27de8d0 100644 --- a/drivers/xen/xenbus/xenbus_xs.c +++ b/drivers/xen/xenbus/xenbus_xs.c @@ -569,16 +569,20 @@ int xenbus_scanf(struct xenbus_transaction t, const char *dir, const char *node, const char *fmt, ...) { va_list ap; - int ret; + int ret =3D 0; + unsigned int len; char *val; =20 - val =3D xenbus_read(t, dir, node, NULL); + val =3D xenbus_read(t, dir, node, &len); if (IS_ERR(val)) return PTR_ERR(val); + if (strlen(val) !=3D len) + goto bad; =20 va_start(ap, fmt); ret =3D vsscanf(val, fmt, ap); va_end(ap); +bad: kfree(val); /* Distinctive errno. */ if (ret =3D=3D 0) @@ -636,15 +640,18 @@ int xenbus_gather(struct xenbus_transaction t, const = char *dir, ...) while (ret =3D=3D 0 && (name =3D va_arg(ap, char *)) !=3D NULL) { const char *fmt =3D va_arg(ap, char *); void *result =3D va_arg(ap, void *); + unsigned len; char *p; =20 - p =3D xenbus_read(t, dir, name, NULL); + p =3D xenbus_read(t, dir, name, &len); if (IS_ERR(p)) { ret =3D PTR_ERR(p); break; } - if (fmt) { - if (sscanf(p, fmt, result) =3D=3D 0) + if (strlen(p) !=3D len) + ret =3D -EINVAL; + else if (fmt) { + if (sscanf(p, fmt, result) <=3D 0) ret =3D -EINVAL; kfree(p); } else --=20 Sincerely, Demi Marie Obenour (she/her/hers) Invisible Things Lab